Thank you for posting to us here on the Community.
I am very sorry to hear you are having issues setting up your Hub on the Connect app.
The first thing to be aware of is you need to be connected to your Home WiFi in order for the app to connect to the Hub. It won't allow the connection if you're on a Guest network, VPN or Mobile data. If this still doesn't help, try clearing the data within the Connect App. These steps will help you do that:
For your Apple device, you can try this: Open Settings > Tap your name > Tap iCloud > Tap Manage Settings > Tap the Connect App > Tap Delete Data.
For your Android device, you can try this: Open settings > Apps > Connect App > Storage > Clear data / Clear cache.
Pop back and keep us posted.